HIV is still a major concern in the U.S., particularly among young people and in specific communities.

Planned Parenthood is offering free testing at participating locations during regular business hours.

"In the United States, more than 1.1 million people are living with HIV, and almost one in six doesn't know it. You can't tell by looking at someone if they are infected HIV - the only way to know is to get tested," Adam Reilly, Planned Parenthood's HIV project manager, said via a release. "National HIV Testing Day is a reminder that getting tested is an important step in stopping the spread of HIV and taking care of ourselves."

"Planned Parenthood provides affordable, convenient HIV testing and sexual health information for women, men and young people in health centers across the country and throughout the year," Reilly said. "Our doors are open to everyone, and we're here for any questions or concerns you might have."

The group said HIV testing is quick and painless. The new rapid HIV tests can provide results in as fast as 20 minutes from just a swab inside the mouth.